org.apache.lucene.codecs.perfield
Class PerFieldPostingsFormat

java.lang.Object
  org.apache.lucene.codecs.PostingsFormat
      org.apache.lucene.codecs.perfield.PerFieldPostingsFormat

All Implemented Interfaces:

NamedSPILoader.NamedSPI

public abstract class PerFieldPostingsFormat
extends PostingsFormat

Enables per field format support.

Note, when extending this class, the name (PostingsFormat.getName()) is written into the index. In order for the field to be read, the name must resolve to your implementation via PostingsFormat.forName(String). This method uses Java's Service Provider Interface to resolve format names.

Files written by each posting format have an additional suffix containing the format name. For example, in a per-field configuration instead of _1.prx filenames would look like _1_Lucene40_0.prx.

See Also:

ServiceLoader

WARNING: This API is experimental and might change in incompatible ways in the next release.

Field Summary

static String	PER_FIELD_FORMAT_KEY
static String	PER_FIELD_NAME
static String	PER_FIELD_SUFFIX_KEY

Fields inherited from class org.apache.lucene.codecs.PostingsFormat

EMPTY

Constructor Summary

PerFieldPostingsFormat()

Method Summary

FieldsConsumer	fieldsConsumer(SegmentWriteState state) Writes a new segment
FieldsProducer	fieldsProducer(SegmentReadState state) Reads a segment.
abstract PostingsFormat	getPostingsFormatForField(String field)

Methods inherited from class org.apache.lucene.codecs.PostingsFormat

availablePostingsFormats, forName, getName, reloadPostingsFormats, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

PER_FIELD_NAME

public static final String PER_FIELD_NAME

See Also:

Constant Field Values

PER_FIELD_FORMAT_KEY

public static final String PER_FIELD_FORMAT_KEY

PER_FIELD_SUFFIX_KEY

public static final String PER_FIELD_SUFFIX_KEY

Constructor Detail

PerFieldPostingsFormat

public PerFieldPostingsFormat()

Method Detail

fieldsConsumer

public FieldsConsumer fieldsConsumer(SegmentWriteState state)
                              throws IOException

Description copied from class: PostingsFormat

Writes a new segment

Specified by:

fieldsConsumer in class PostingsFormat

Throws:

IOException

fieldsProducer

public FieldsProducer fieldsProducer(SegmentReadState state)
                              throws IOException

Description copied from class: PostingsFormat

Reads a segment. NOTE: by the time this call returns, it must hold open any files it will need to use; else, those files may be deleted. Additionally, required files may be deleted during the execution of this call before there is a chance to open them. Under these circumstances an IOException should be thrown by the implementation. IOExceptions are expected and will automatically cause a retry of the segment opening logic with the newly revised segments.

Specified by:

fieldsProducer in class PostingsFormat

Throws:

IOException

getPostingsFormatForField

public abstract PostingsFormat getPostingsFormatForField(String field)